The Jewish Calendar and Holidays (incl. Sabbath): The Sabbath: Using a Toothbrush on Shabbos:
Is it allowed to use a toothbrush on Shabbos?
Rav Moshe Feinstein (Igros Moshe, Orach Chaim, Vol. 1, No. 112) states that it is permitted to use a toothbrush on
Shabbos, but not toothpaste. Thus it is allowed to put water or mouthwash in your mouth and then brush your teeth. It is
preferable to have a special toothbrush set aside for Shabbos. Even if your gums frequently bleed, it is permitted to brush,
but you should use a soft brush.